Diagnostic and therapeutic gastrointestinal endoscopy is commonly used to gain access to the digestive tract for the purpose of observing and removing tissue. Common endoscopic therapeutic procedures include cutting, ablating and unclogging through various known mechanisms.
Techniques for obtaining tissues for biopsies include the use of forceps (with or without coagulation), snares or, for cytologic examination, needles and brushes. While these techniques permit the accomplishment of many diagnostic and/or therapeutic goals, in some instances they are inadequate. For example, there currently exists no satisfactory procedure for the removal of flat malignant mucosal lesions or lesions in the submucosa. On some occasions, deep specimens are required for a diagnosis (e.g. lymphoma or Menetrier's disease) in which cases current procedures are limited. Techniques such as "lift and cut" resection and polypectomy after a submucosal injection of a saline or glucose solution have been used but these procedures are not always successful because on some occasions the tissue does not elevate and in others the injection may actually flatten the area making tissue removal more difficult. These procedures, known as endoscopic mucosectomy are becoming increasingly popular, particularly in Japan where early gastric cancer is common.
Early esophageal cancer is an important problem in many parts of the world. With appropriate screening tests, the diagnosis can be made when the disease is limited to the mucosa or even in a premalignant phase. There are known procedures for the destruction of early esophageal cancer (e.g. laser photocoagulation) but there is an existing need for a procedure which will permit the efficient and complete removal of tissue from patients with early esophageal cancer and in the other conditions described above.
It is an object of this invention to provide an improved method for the removal of cancerous and precancerous tissue within the gastrointestinal tract.